'yum update' stopped working

[Trevor Smith]

I tried using yum to install some ati drivers, then backed out with an 'rpm 
-e ...' command (because X wouldn't start afterwards), and now I'm trying to 
use:

yum update

to update the remaining installed packges on my system but it keeps reporting 
the same thing:

[root at localhost trevor]# yum update
Gathering header information file(s) from server(s)
[...snip...]
Finding updated packages
Downloading needed headers
Resolving dependencies
.Package newpg needs libksba.so.0, this is not available.

Is this due to me 'manually' removing the ati rpm (and the 
kernel-module-fglrx... rpm that went with it)? Or is it a transient problem 
with some yum repositories? Or is it something else?

yum install ..., yum update, etc. have always "just worked" for me before.

-- 
Trevor Smith // trevor at haligonian.com